The object of the invention described hereinafter is a combination capping film for sealing a wide variety of packages intended for conservation of foodstuffs, prevention of oxidation, corrosion or loss of contents, and for other applications where hermetic sealing is essential but where ease of opening must be guaranteed.
Experience has shown that two conflicting requirements must be satisfied for hermetic sealing of packages with capping films: on the one hand, the package must be hermetically sealed even if constituents, for example drops of the contents, fall onto the sealing area during filling, but on the other hand, the user must be able to remove the capping film in order to open the package. If the sealing seam is sealed under high temperature and pressure, some of the contents may be extruded through the sealing area; this ensures satisfactory sealing, but the desired peel effect, which facilitates opening by the user, is thereby impaired. This problem is frequently encountered when opening ordinary yoghourt beakers.
However, sealing of packages by adjustable parameter which guarantee maximal ease of opening results in extrusion of greater quantities of material during processing and in imperfectly sealed goods.
The invention described hereinafter is designed, on the one hand, to eliminate conflicting sealing requirements (hermetically sealed seam/peel effect) and on the other to facilitate opening of the package by the user.